Agricultural commercial vehicles or tractors can be equipped with a multitude of different working or planting equipment which are used for different agricultural working functions. The working equipment is generally driven either mechanically or hydraulically, for instance by means of a so-called power take-off shaft, which is driven by the combustion engine of the tractor. Disadvantageous is the dependence of the power take-off shaft rotational speed in relationship to the rotational speed of the motor which does not match the respective optimum rotational speed of the different working equipment.
Therefore, it has already been proposed to electrically drive the working equipment which is connected to the tractor, to disengage the drive rotational speed for the working equipment from the drive rotational speed of the combustion engine of the tractor. Through EP 1 995 108 A1, a device for the electrical supply of planting equipment, coupled to a commercial vehicle, is known. Positioned in the drive train of the tractor is a generator which is driven by an internal combustion engine (referred to herein as a combustion engine), which generates electrical energy that is transferred by means of an electric transmission device to the planting equipment. At least an electric motor is positioned in the planting equipment which performs the agricultural working function, the electric motor receives the electric supply and electrical energy through electric wiring and a plug-in connection at the tractor. The electric power which is applied to the electric motor can be adjusted through the transmission device, thus, the drive rotational speed of the electric motors are independent of the rotational speed of the combustion engine. However, it is a disadvantage that the total drive power for the planting device is induced as by electrical power which creates a decrease of the efficiency, meaning an increased gasoline consumption of the combustion engine of the tractor.